Electron-stimulated oxidation of beryllium by water vapor and by oxygen

This is the authors' abstract. We don't add key points for this paper.

Pronounced effects of electron-stimulated oxidation (ESO) of Be by water vapor, as opposed to much weaker ESO of Be by O₂, were observed, reaching maximal possible oxidation rates for a ratio of ~150 impinging electrons per water molecule. Moreover, a continuous shift of the oxygen Auger electron spectroscopy line to higher values with increased exposure was observed only in case of water vapor ESO. This suggests that the mechanism involved is of a Mott-Cabrera type, enabled by a combination of electric field triggered by negative OH and∕or oxygen ions formed at the surface, probably by secondary electron attachment, and a very fast diffusion of Be⁺⁺ ions that may be caused by the presence of hydrogen in the oxide layer. The water vapor ESO exhibits an inverse dependence on the substrate temperature, mainly due to the decrease with temperature of negative ions concentration on the surface, leading to weakening of the electric field formed across the oxide.